Chisu Valentina, Mura Lorena, Foxi Cipriano, Masala Giovanna
Istituto Zooprofilattico Sperimentale della Sardegna, Via Duca degli Abruzzi, 8, 07100, Sassari, Italy.
Acta Parasitol. 2021 Jun;66(2):654-663. doi: 10.1007/s11686-020-00324-w. Epub 2021 Jan 25.
Coxiella burnetii is known for its potential as veterinary and human bacterial pathogen. The bacteria have been described in ticks, but their role in transmission of Q fever in humans is considered low. Coxiella endosymbionts closely related to C. burnetii have been also isolated from an extensive range of tick species and evidence is growing that these endosymbionts could be linked to human bacteremia. The aim of this study was to get new information on the presence of Coxiella species in ticks infesting wild and domestic hosts in Sardinia, Italy.
Here, 138 ticks collected from the study area were analyzed for the presence of C. burnetii and Coxiella-like bacteria by polymerase chain reaction (PCR), sequencing and philogenetic analyses using a set of primers targeting the 16S rRNA gene.
DNA of Coxiella species was detected in 69% of the total ticks examined. Based on phylogenetic analysis, the 16S rRNA Coxiella genotypes identified in this study grouped in strongly supported monophyletic clades with identified reference sequences of CLEs detected from Rhipicephalus, Dermacentor, Haemaphysalis and Ornithodoros species and with Coxiella burnetii strains isolated worldwide.
This study reports the molecular detection of a high diversity of Coxiella-like bacteria in Sardinian ticks and confirms also the presence of C. burnetii in tick species previously identified in the island. The role that Coxiella-like endosymbionts play in Sardinian ticks and in their vertebrate hosts needs to be explored further.
伯氏考克斯体作为一种兽医和人类细菌病原体而闻名。这种细菌已在蜱虫中被发现，但其在人类Q热传播中的作用被认为较低。与伯氏考克斯体密切相关的考克斯体内共生菌也已从广泛的蜱虫种类中分离出来，并且越来越多的证据表明这些内共生菌可能与人类菌血症有关。本研究的目的是获取有关意大利撒丁岛野生和家养宿主身上蜱虫中考克斯体种类存在情况的新信息。
在此，通过聚合酶链反应（PCR）、测序以及使用一组靶向16S rRNA基因的引物进行系统发育分析，对从研究区域采集的138只蜱虫进行了伯氏考克斯体和类考克斯体细菌的检测。
在所检测的全部蜱虫中，69%检测到了考克斯体种类的DNA。基于系统发育分析，本研究中鉴定出的16S rRNA考克斯体基因型与从璃眼蜱属、革蜱属、血蜱属和钝缘蜱属物种中检测到的已鉴定参考序列的类考克斯体内共生菌以及全球分离出的伯氏考克斯体菌株归为得到有力支持的单系分支。
本研究报告了在撒丁岛蜱虫中对高度多样的类考克斯体细菌的分子检测，同时也证实了在该岛先前鉴定出的蜱虫种类中存在伯氏考克斯体。类考克斯体内共生菌在撒丁岛蜱虫及其脊椎动物宿主中所起的作用需要进一步探索。
